Wielding rifles and wearing balaclavas, the volunteers are trained by the Ukrainian army and have signed up to defend their country against Russia's onslaught.

"Most of those who are here aren't soldiers. They're just civilians who want to defend their country -- 50 percent of them have never held a weapon until today," said a sergeant known as "Ticha".

Russian troops invaded Bucha, a northwestern suburb of Kyiv, three days after their offensive in Ukraine began on February 24.

They withdrew in April as part of a major redeployment to the east, leaving a trail of civilian corpses -- some with their hands bound -- behind them, sparking accusations of war crimes.

Many of the Ukrainians who have swelled the ranks of the army following the invasion have received training in a forest previously occupied by Russian soldiers.

The volunteers have reclaimed the area, now pockmarked by piles of earth, shelters and gigantic holes after the invading troops abandoned the site.

"The Russians dug these holes, 7,000 big holes for armoured vehicles, tanks, tankers. It's a lot, and they were preparing to stay here for a long time," said Ukrainian territorial defence force spokesman Valentyn Kalachnyk.

Ticha told AFP the exercises, which took place under the watchful eye of Ukrainian army staff, would leave the locals better prepared if Moscow's forces invaded Bucha again.

"If the Orcs (Russian soldiers) come back, God forbid, we will be able to deal with them, unlike the first time. We weren't prepared for that," he said.

"We teach them what we know, more than what you learn from the instructors sent by NATO."

Kalachnyk added: "There are constant exercises here. There are a lot of volunteers, there are always queues in the military enlistment offices to join the army."